1. Field of the Invention
The present invention relates to a flat panel display apparatus, and more particularly, to a flat panel display apparatus improved in a grounding structure of a control PCB (printed circuit board).
2. Description of the Related Art
A flat panel display apparatus includes an LCD (liquid crystal display), a PDP (plasma display panel), a VFD (vacuum fluorescent display), an FED (field emission display), an ELD (electro luminescence display), etc.
Making of the LCD includes arranging a plurality of TFTs (thin film transistors) onto a transparent glass substrate through a semiconductor thin film process, and forming a pixel electrode related to each TFT. Here, the transparent glass substrate containing the TFTs will be called a TFT array substrate.
In correspondence to the pixel electrode formed on the TFT array substrate, there is provided a common electrode formed on a color filter substrate so as to allow an electric field to be produced between the pixel electrode and the common electrode when voltage is applied to the pixel electrode. Here, the color filter substrate is spaced from the TFT array substrate at a predetermined distance. Further, between the TFT array substrate and the color filter substrate are filled liquid crystals which move according to the electric field.
As a method bonding an LCD driver IC (integrated chip) to the TFT array substrate, there are a TAB (tape automated bonding) method, a COG (chip on glass) method, etc.
In the TAB method, the LCD driver IC is attached to a flexible TCP (tape carrier package), and a first end of the TCP is connected to one front edge of the TFT array substrate and a second end thereof is connected to a source PCB (printed circuit board). Then, the source PCB is connected to a control PCB.
In the COG method, the LCD driver IC is directly mounted on the TFT array substrate by flip chip technology, being connected with a gate bus-line and a data bus-line formed on the TFT array substrate. Then, the TFT array substrate is connected to the control PCB through an FPC (flexible printed circuit). Here, the FPC is connected to the gate and data bus-lines in the middle of the one front edge of the TFT array substrate on which the LCD driver IC is mounted, thereby transmitting a predetermined control signal from the control PCB to the LCD driver IC. The COG method can decrease the packaging size and the production cost of the LCD, so that a COG type LCD is being widely used today.
The control PCB is provided in the rear of the flat panel display module on which a picture is displayed. While the LCD operates, the control PCB produces an EMI (electromagnetic interference) disturbing the performance of the LCD, e.g., deteriorating the picture being displayed. Therefore, the control PCB should be grounded so as to prevent the EMI.
Generally, in the case of the LCD like a TAB type LCD, in which the length of the control PCB or the source PCB is approximately equal to the width of the flat panel display module, either the control PCB or the source PCB is provided with a conductive grounding part on opposite ends thereof, and the conductive grounding part is combined to a chassis forming an outer enclosure of the flat panel display module with screws, so that the control PCB is both grounded and combined to the chassis.
However, if the LCD has the control PCB whose length is shorter than the width of the flat panel display module, it is difficult to ground the control PCB in the above-described manner. For example, in the case of the COG type LCD, the control PCB is placed in the middle of the rear edge area of the flat panel display module, and the FPC has the width shorter than that of the flat panel display module and is placed in the middle of the edge of the flat panel, so that it is difficult to ground the control PCB in the above-described manner using the screws.